Tex-Mex Yellow Squash Casserole (with Leftover Cornbread)

If you’re staring at a pan of leftover cornbread and a pile of summer squash, wondering what to do next, this recipe might just become your new favorite. The Tex-Mex Yellow Squash Casserole blends savory, cheesy, and spicy flavors in a dish that is easy to make, incredibly satisfying, and perfect for any season.

This casserole is also a genius way to repurpose stale cornbread, which otherwise may go to waste. It’s the perfect combination of comfort food and veggie-forward creativity, bringing together sautéed vegetables, cheddar cheese, green chiles, and a Tex-Mex kick that elevates a humble vegetable casserole into a crowd-pleaser.

In case you’re new to handling squash, here’s a helpful guide on how to store summer squash so it lasts longer and maintains its flavor. And if you’re thinking ahead to future meals, here’s a clever collection of leftover cornbread ideas to keep your fridge exciting and waste-free.

What Is Tex-Mex Yellow Squash Casserole?

The Tex-Mex Yellow Squash Casserole is a spicy twist on traditional Southern squash bakes. It fuses classic squash casserole elements—like melted cheese and baked vegetables—with the bold flavors of Tex-Mex cuisine, such as green chiles, cumin, and colorful bell peppers.

Unlike other casseroles that might rely heavily on breadcrumbs or white sauces, this one uses crumbled leftover cornbread, which adds texture and a subtle sweetness that complements the spices beautifully. It’s great as a vegetarian main dish or as a flavorful side at potlucks and holiday tables.

For more background on the roots and flavor profile of Tex-Mex cooking, check out this fantastic explanation of what is Tex-Mex.

Ingredients You’ll Need

Here’s what goes into making this comforting and satisfying dish:

• 4 cups of chopped yellow squash (about 3 small or 2 medium)
• 2 tbsp butter
• ½ medium onion, chopped
• ½ cup of chopped bell peppers (red, yellow, or green)
• 8 oz white mushrooms, sliced
• ¼ tsp ground cumin
• 1 tbsp all-purpose flour
• 1 cup milk (any type, including low-fat or evaporated)
• 1 cup frozen corn
• 4 oz green chiles (adjust to spice preference)
• 1 cup of crumbled leftover cornbread or boxed stuffing mix
• 1 cup shredded cheese (cheddar, Monterey Jack, or pepper jack)
• Salt and freshly ground black pepper to taste

Step-by-Step Instructions

Follow these steps for a perfect bake every time:

1. Cook the Squash
   • Place chopped yellow squash in a microwave-safe bowl.
   • Add a tablespoon of water, cover, and microwave on high for 8–9 minutes until tender.
   • Drain well and mash lightly with a fork to release excess moisture.
2. Sauté the Vegetables
   • In a large skillet, melt the butter over medium-high heat.
   • Add chopped onions and bell peppers; sauté until soft.
   • Add mushrooms and continue cooking for 2–3 more minutes.
   • Sprinkle in the cumin and mix well.
3. Make the Sauce
   • Stir in the flour to the sautéed mixture and cook for 1–2 minutes.
   • Gradually add the milk, stirring constantly, until a thickened sauce forms.
4. Mix Everything Together
   • Combine the mashed squash, corn, green chiles, and the sautéed vegetable mixture.
   • Season with salt and pepper.
   • Fold in the crumbled leftover cornbread and cheese.
   • Mix gently to keep the texture intact.
5. Bake the Casserole
   • Pour the mixture into a greased baking dish.
   • Bake at 400°F (200°C) for 20 minutes.
   • Sprinkle additional cheese on top for the last 5 minutes of baking if desired.

Make-Ahead, Freezing, and Storage Tips

• Assemble the casserole up to a day in advance, refrigerate, and bake fresh.
• Leftovers freeze well: wrap tightly in foil and use within 2 months.
• Reheat in the oven or microwave, adding a splash of milk if it looks dry.

What to Serve With It

This casserole pairs well with:

• Grilled smoked sausage
• A side of refried beans or Mexican rice
• Crisp green salads with vinaigrette
• Sliced avocado or a drizzle of hot sauce for extra kick

It also holds up as a stand-alone vegetarian main course for lunch or dinner.

Variations and Customizations

Want to make it your own? Try these ideas:

• Add black beans or pinto beans for extra protein
• Mix in diced tomatoes or jalapeños for more flavor
• Swap cheese types—try pepper jack for more heat
• Add rotisserie chicken or ground turkey for a meaty version
• Use zucchini alongside squash for color and variety
• Make it vegan: use plant-based cheese, non-dairy milk, and oil instead of butter

Common Mistakes to Avoid

• Too much moisture: Drain the squash well to prevent sogginess.
• Over-seasoning: If you use boxed stuffing, it may already be salty.
• Overbaking: Keep an eye out during the last 5 minutes to avoid drying out the casserole.

Nutritional Profile

A rough estimate per serving (1/10th of the casserole):

• Calories: ~270 kcal
• Protein: ~9g
• Carbs: ~35g
• Fat: ~11g
• Fiber: ~3g
• Gluten-Free: Use gluten-free cornbread or stuffing mix
• Vegetarian: Yes

FAQs

Can you freeze Tex-Mex squash casserole?
Yes! Freeze tightly wrapped leftovers. Thaw overnight in the fridge and reheat in the oven or microwave.

What is the best way to use leftover cornbread?
Aside from casseroles, use it for croutons, stuffing, or bread pudding. Try drying it in the oven at 300°F for 15 minutes to make it more usable.

What kind of squash is best for casseroles?
Yellow summer squash or zucchini work best due to their mild flavor and tender texture.

Can you use canned squash in a casserole?
You can, but it may be too watery. Drain thoroughly and adjust cooking time as needed.

How do you keep squash casserole from getting watery?
Cook and mash the squash, then drain it well before mixing with other ingredients.

What’s the difference between Tex-Mex and traditional squash casseroles?
Tex-Mex adds spice, color, and bold flavor using ingredients like green chiles, cumin, and cheddar cheese, whereas traditional versions may use milk, butter, and eggs in a more subtle, creamy base.

Final Thoughts

The Tex-Mex Yellow Squash Casserole is a practical, flavorful, and inventive way to make the most of seasonal produce and kitchen leftovers. It’s comforting enough for a holiday dinner yet simple enough for a weeknight meal. Whether you serve it with grilled meat or enjoy it as a veggie main, this casserole is bound to become a favorite at your table.